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The oxygen evolving complex (OEC) of photosystem II catalyzes the oxidation of water to form molecular oxygen. The S₃-state is currently the last observable intermediate prior to O–O bond formation. Its electronic structure has been assigned to a homovalent Mn(IV)₄ core with an S = 3 ground state. In a recent publication (Lee, Marchiori, et al. JACS), the Agapie (Caltech) and Britt labs synthesized and characterized via XAS and multifrequency EPR spectroscopy a Mn(IV)₄O₄ cuboidal complex.

In a new JACS article (https://pubs.acs.org/doi/10.1021/jacs.9b10273) describing a collaboration between the Britt and Gray (Caltech) labs, Sayler et al. describe a set of model materials that facilitate the understanding of individual active sites in the highly active heterogeneous water oxidation catalyst, [NiFe] LDH.  Heterogeneous catalysts often have a high magnetic density of active sites, complicating the interpretation of EPR spectroscopic data.

Thermoelectric materials have been used to provide electricity to spacecraft for decades. In this work the Kauzlarich lab (Perez, et al., ACS Appl. Energy Mater., 2020) in collaboration with Thermal Energy Conversion Research and Advancement Group at NASA-JPL have shown that Yb₁₄MgSb₁₁, one of the candidates for NASA’s next generation of thermoelectric materials, can be composited with iron without reaction upon thermal cycling.

Hydrogenases are nature’s machines to metabolize H₂. The [FeFe] hydrogenase subtype catalyzes the rapid turnover at its six-iron active site cofactor, the H-cluster, which contains CO, cyanide and a unique azadithiolate (adt) ligand essential for catalysis. In a recent publication (Rao and coworkers, Chemical Science, 2019) the Britt lab identified the biosynthetic precursor of the adt ligand.

Cesium lead iodide (CsPbI₃) has long been a promising light absorbing material for perovskite solar cells. Researchers from the Navrotsky lab, in a recently published study (J. Am. Chem. Soc. 2019, 141, 14501) conducted calorimetric studies on cubic(α) and orthorhombic(δ) CsPbI₃ polymorphs, obtaining their enthalpies of formation from binary iodides, and discussing the relative stabilities. Cubic phase CsPbI₃, the desirable phase for light absorbing material, is confirmed to be metastable under ambient conditions.

In the most recent Science, Professor R. David Britt and Chemistry PhD student David Marchiori review the latest X-ray free electron laser structure of flash generated higher oxidations states of the photosystem II oxygen evolving complex (M.

[FeFe]-hydrogenases catalyze H₂ evolution at extraordinary rates at low overpotential using base metal (not platinum). In the field of renewable energy, the biosynthesis of these enzymes’ active sites, the H-cluster, is of intense interest. Among its many cofactors, the azadithiolate is unique, and its biosynthesis remains enigmatic. Three Fe–S proteins, HydE, HydF, and HydG, are essential for the H-cluster bioassembly. This paper describes an in vitro assembly approach where a synthetic [Fe(cysteine)(CO)₂(CN)] complex, “syn-B,” allows HydG- free biosynthesis of the active enzyme.

In a recent publication "Trapping and Electron Paramagnetic Resonance Characterization of the 5′dAdo• Radical in a Radical S-Adenosyl Methionine Enzyme Reaction with a Non-Native Substrate", Rick Sayler and coworkers in R. David Britt's Lab at UC Davis used non-natural substrates in the HydG radical SAM enzyme to trap and characterize the hot 5'deoxyadenosyl radical for the first time in such an enzyme reaction.

More information at https://pubs.acs.org/doi/10.1021/acscentsci.9b00706

Thermoelectric materials have shown promise as a clean energy alternative to fossil fuels that can convert waste heat into electrical power.  The Kauzlarich lab (He et al., Chem. Mater., 2019), in collaboration with Prof. Donadio and NASA-JPL, have been able to elucidate the structural and physical properties of a new material, Yb₂₁Mn₄Sb₁₈, showing large thermoelectric efficiency in the mid-to-high temperature regime.  The favorable properties of Yb₂₁Mn₄Sb₁₈ come intrinsically from its unique crystal structure, highlighted below. 

In a recent publication (Perryman and coworkers, Materials Horizons, 2019) the Velázquez Lab describes for the first time experimental evidence of CO₂ reduction (CO₂R) activity over the compositionally modular Chevrel-Phase chalcogenide framework. In this unique framework, “promotion” of Mo₆S₈ units by a ternary metal species allows for electronic tuning of CO₂R-active sites, and further acts to stabilize anionic domains of key reaction intermediates, thereby providing an avenue toward controllable catalytic selectivity.